I guess I never really thought about it that much.
The "apps" I use more than anything are webconferencing apps, and in particular, the mute button. Almost without exception (I would say without exception, but there are a few webconferencing apps I don't use often enough to know for sure), the mute button basically shows you the current status. That is, when you are not muted, it shows a picture of a mic. When you click it, it puts a line through the mic, or highlights it in red to indicate it is OFF. This make it very easy to glance at and see if my mic is on or not.
I think about the app buttons the same way. When I look at the fan, if it's got a line through it, I know the fan is not on. When I look at the lock, I know whether it's locked or not. True, the frunk button is different in that it shows the frunk being open, but I suspect this is more about highlighting what the button is, because without the popped frunk it would just look like the front of a car. I can live with that because the frunk open/closed is not a status I really need to check on normally.
So, in my opinion, no, the buttons are not backwards. They are just as they should be.